My research focuses on the processes controlling debris-flow initiation and growth, particularly after wildfire, but also in unburned areas.
This research includes a field component that obtains direct measurements of debris flows in natural settings, a modeling component that seeks to explain the observations, and an applied component that focuses on assessment of debris-flow hazards. My previous research at the USGS focused on river mechanics, including bank erosion and the development of model-based approaches to gage streams and rivers.
Education and Certifications
University of Colorado, Ph.D., 2003, Civil Engineering
University of Colorado, M.S., 1998, Civil Engineering
Cornell University, B.S., 1994, Civil Engineering
Science and Products
Calwood Fire "Heil Ranch" Landslide Monitoring Site near Boulder, CO
Wildfire can radically change a mountainous landscape such that even a modest rainstorm is capable of producing deadly and destructive flash flooding and debris flows.
Postfire Landslide Monitoring Station: "Chips" (2021 Dixie Fire) near Belden, CA
Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.
Postfire Landslide Monitoring Station: "Chambers" (2021 Dixie Fire) near Belden, CA
Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.
Advancing Post-Fire Debris Flow Hazard Science with a Field Deployable Mapping Tool
Mapping the occurrence of post-fire flooding and debris flow is crucial for 1) integrating observations into models used to define rainfall thresholds for early warning, 2) understanding patterns of inundation, and 3) improving models for predictive hazard assessment. Despite the critical role mapping plays in post-fire hazard assessment and early warning, there has not been a standardized approa
How Often Do Rainstorms Cause Debris Flows in Burned Areas of the Southwestern U.S.?
Debris flows, sometimes referred to as mudslides, mudflows, lahars, or debris avalanches, are common types of fast-moving landslides. They usually start on steep hillsides as a result of shallow landslides, or from runoff and erosion that liquefy and accelerate to speeds in excess of 35 mi/h. The consistency of debris flows ranges from thin, watery to thick, rocky mud that can carry large items...
Emergency Assessment of Post-Fire Debris-Flow Hazards
Estimates of the probability and volume of debris flows that may be produced by a storm in a recently burned area, using a model with characteristics related to basin shape, burn severity, soil properties, and rainfall. Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS...
2009 Station Fire, Dunsmore Canyon, Glendale, California
In 2009, the Station Fire burned 160,000 acres in the San Gabriel Mountains. Vegetation has started to return, but it can take many years for a basin to fully recover from the effects of fire.
Reconstruction of an Avalanche: The West Salt Creek Rock Avalanche
Release Date: MAY 25, 2016 The West Salt Creek Rock Avalanche, Colorado, May 25, 2014
Rainfall and Landslides in Southern California
A summary of recent and past landslides and debris flows caused by rainfall in Southern California.
Field-verified inventory of postfire hydrologic response for the 2020 CZU Lightning Complex, River, Camel, and Dolan Fires following a 26-29 January 2021 atmospheric river storm sequence
This data release is a field-verified inventory of postfire hydrologic response for the 2020 CZU (San Mateo–Santa Cruz Unit) Lightning Complex, River Fire, Camel Fire, and Dolan Fire following a 26-29 January 2021 atmospheric river storm sequence. Postfire hydrologic response types include a) no response, b) minor response, and c) major response. A “minor” response was deemed capable of impairing
Field-verified inventory of postfire debris flows for the 2021 Dixie Fire following a 23-25 October 2021 atmospheric river storm and 12 June 2022 thunderstorm
Summary
This data release is a field-verified inventory of postfire debris flows for the 2021 Dixie Fire following a 23-25 October 2021 atmospheric river storm and 12 June 2022 thunderstorm. The “README.txt” file describes the fields for the “Inventory.csv” file. The “Chambers” and “Chips” rain gage data referenced in the inventory are included as: “Chambers-Oct2021-Storm.csv”, “Chambers-Jun2022-S
Debris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2019
Chalk Cliffs, located 8 miles southwest of Buena Vista, Colorado, is a natural laboratory for research on runoff-initiated debris flows (Coe et al., 2010). In 2019, there were two monitoring stations operating at Chalk Cliffs. The Upper Station drains an area of 0.06 km2 and was used to monitor flow properties and triggering conditions in the headwaters of the study area. It was equipped with two
Debris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2015
Chalk Cliffs, located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, e
Debris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2016
Chalk Cliffs located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, et
Data supporting an analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States
This data release supports the analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States. We define the recurrence interval of the peak 15-, 30-, and 60-minute rainfall intensities for 316 observations of post-fire debris-flow occurrence in 18 burn areas, 5 U.S. states, and 7 climate types. These data support the analysis described in Staley
Debris-flow monitoring data, Chalk Cliffs, Colorado, USA, 2014
This data release includes 2014 time-series data from three debris-flow monitoring stations at Chalk Cliffs in Chaffee County, Colorado, USA. The data were collected to help identify the triggering conditions, magnitude, and mobility of debris flows at the site. The three stations are located sequentially along a channel draining the 0.3 km^2 study area. The Upper, Middle, and Lower stations have
Monitoring environmental controls on debris-flow sediment supply, Chalk Cliffs, Colorado, 2011 to 2015
This data release includes time-series data of rock temperature, air temperature, wind speed, and humidity at the Chalk Cliffs debris-flow monitoring site in central Colorado (Latitude: 38.73330, Longitude: -106.18704). The data were collected to help identify the environmental controls on rates of rockfall, which is the primary source of debris-flow material at the site. Data were recorded at 1-m
Post-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017
This data release includes time-series data from a monitoring site located in a small (0.12 km2) drainage basin in the Las Lomas watershed in Los Angeles County, CA, USA. The site was established after the 2016 Fish Fire and recorded a series debris flows in the first winter after the fire. The station is located along the channel at the outlet of the study area (34 9'18.50"N, 117 56'41.33"W, WGS8
Debris-flow inundation and damage data from the 9 January 2018 Montecito Debris-Flow Event
On 9 January 2018, intense rain above Montecito, California triggered a series of debris flows from steep catchments in the Santa Ynez Mountains. These catchments were burned three weeks earlier by the 1140 km2 Thomas Fire. After exiting the mountain front, the debris flows traveled over 3 km down a series of alluvial fans, killing 23 people and damaging over 400 homes. To understand the flow dyna
Post-wildfire debris-flow monitoring data, Arroyo Seco, 2009 Station Fire, Los Angeles County, California, November 2009 to March 2010.
This data release includes time-series data from a monitoring site located in a small drainage basin in the Arroyo Seco watershed in Los Angeles County, CA, USA (N3788964 E389956, UTM Zone 11, NAD83). The site was established after the 2009 Station Fire and recorded a series debris flows in the first winter after the fire. The data include three types of time-series: (1) 1-minute time series of ra
Map and model input and output data covering N 40.0 40.375 and W 105.25 105.625 in the northern Colorado Front Range for analysis of debris flow initiation resulting from the storm of September 9 13, 2013
Rainfall on 913 September 2013 triggered at least 1,138 debris flows in a 3430 km2 area of the Colorado Front Range. Most flows were triggered in response to two intense rainfall periods, one 12.5-hour-long period on 1112 September, and one 8-hour-long period on 12 September. Data in this project pertain to an area bounded by N 40.0 40.375 and W 105.25 105.625 which includes many of the areas wh
Filter Total Items: 83
How long do runoff-generated debris-flow hazards persist after wildfire?
Runoff-generated debris flows are a potentially destructive and deadly response to wildfire until sufficient vegetation and soil-hydraulic recovery have reduced susceptibility to the hazard. Elevated debris-flow susceptibility may persist for several years, but the controls on the timespan of the susceptible period are poorly understood. To evaluate the connection between vegetation recovery and d
Authors
Andrew Paul Graber, Matthew A. Thomas, Jason W. Kean
Toward probabilistic post-fire debris-flow hazard decision support
Post-wildfire debris flows (PFDF) threaten life and property in western North America. They are triggered by short-duration, high-intensity rainfall. Following a wildfire, rainfall thresholds are developed that, if exceeded, indicate high likelihood of a PFDF. Existing weather forecast products allow forecasters to identify favorable atmospheric conditions for rainfall intensities that may exceed
Authors
Nina S. Oakley, Tao Liu, Luke McGuire, Matthew Simpson, Benjamin J. Hatchett, Alexander Tardy, Jason W. Kean, Christopher Castellano, Jayme L. Laber, Daniel Steinhoff
Forecasting the inundation of postfire debris flows
In the semi-arid regions of the western United States, postfire debris flows are typically runoff
generated. The U.S. Geological Survey has been studying the mechanisms of postfire debris-flow initiation for multiple decades to generate operational models for forecasting the timing, location, and magnitude of postfire debris flows. Here we discuss challenges and progress for extending operational
Authors
Katherine R. Barnhart, Ryan P Jones, David L. George, Francis K. Rengers, Jason W. Kean
Runout model evaluation based on back-calculation of building damage
We evaluated the ability of three debris-flow runout models (RAMMS, FLO2D and D-Claw) to
predict the number of damaged buildings in simulations of the 9 January 2019 Montecito, California, debris-flow event. Observations of building damage after the event were combined with OpenStreetMap building footprints to construct a database of all potentially impacted buildings. At the estimated event volum
Authors
Katherine R. Barnhart, Jason W. Kean
Postfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn a
Authors
Matthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. Collins
The influence of large woody debris on post-wildfire debris flow sediment storage
Debris flows transport large quantities of water and granular material, such as sediment and wood, and this mixture can have devastating impacts on life and infrastructure. The proportion of large woody debris (LWD) incorporated into debris flows can be enhanced in forested areas recently burned by wildfire, because wood recruitment into channels accelerates in burned forests. In this study, we ex
Authors
Francis K. Rengers, Luke A. McGuire, Katherine R. Barnhart, Ann Youberg, Daniel Cadol, Alexander Gorr, Olivia Joan Andrea Khoury Hoch, Rebecca Beers, Jason W. Kean
The rainfall intensity-duration control of debris flows after wildfire
Increased wildfire activity in the western United States has exposed regional gaps in our understanding of postfire debris-flow generation. To address this problem, we characterized flows in an unstudied area to test the rainfall intensity-duration control of the hazard. Our rainfall measurements and field observations from the northern Sierra Nevada (California, USA) show that debris flows result
Authors
Matthew A. Thomas, Donald N. Lindsay, David B. Cavagnaro, Jason W. Kean, Scott W. McCoy, Andrew Paul Graber
Simulating debris flow and levee formation in the 2D shallow flow model D-Claw: Channelized and unconfined flow
Debris flow runout poses a hazard to life and infrastructure. The expansion of human population into mountainous areas and onto alluvial fans increases the need to predict and mitigate debris flow runout hazards. Debris flows on unconfined alluvial fans can exhibit spontaneous self-channelization through levee formation that reduces lateral spreading and extends runout distances compared to unchan
Authors
Ryan P. Jones, Francis K. Rengers, Katherine R. Barnhart, David L. George, Dennis M. Staley, Jason W. Kean
Postfire debris flow hazards—Tips to keep you safe
Often referred to as “mudflows,” debris flows are a type of landslide made up of a rapidly moving mixture of dirt, rocks, trees, and water (and sometimes ash) that start on a hillside and travel downvalley. They can easily overflow channels and severely damage houses, vehicles, or other structures. Areas burned by wildfires are especially susceptible to these hazards, which can be triggered by sto
Authors
Steven Sobieszczyk, Jason W. Kean
Multi-model comparison of computed debris flow runout for the 9 January 2018 Montecito, California post-wildfire event
Hazard assessment for post-wildfire debris flows, which are common in the steep terrain of the western United States, has focused on the susceptibility of upstream basins to generate debris flows. However, reducing public exposure to this hazard also requires an assessment of hazards in downstream areas that might be inundated during debris flow runout. Debris flow runout models are widely availab
Authors
Katherine R. Barnhart, Ryan P. Jones, David L. George, Brian W. McArdell, Francis K. Rengers, Dennis M. Staley, Jason W. Kean
Movement of sediment through a burned landscape: Sediment volume observations and model comparisons in the San Gabriel Mountains, California, USA
Post-wildfire changes to hydrologic and geomorphic systems can lead to widespread sediment redistribution. Understanding how sediment moves through a watershed is crucial for assessing hazards, developing debris flow inundation models, engineering sediment retention solutions, and quantifying the role that disturbances play in landscape evolution. In this study, we used terrestrial and airborne li
Authors
Francis K. Rengers, Luke A. McGuire, Jason W. Kean, Dennis M. Staley, Mariana Dobre, Peter R. Robichaud, Tyson Swetnam
Postwildfire soil‐hydraulic recovery and the persistence of debris flow hazards
Deadly and destructive debris flows often follow wildfire, but understanding of changes in the hazard potential with time since fire is poor. We develop a simulation‐based framework to quantify changes in the hydrologic triggering conditions for debris flows as postwildfire infiltration properties evolve through time. Our approach produces time‐varying rainfall intensity‐duration thresholds for ru
Authors
Matthew A. Thomas, Francis K. Rengers, Jason W. Kean, Luke A. McGuire, Dennis M. Staley, Katherine R. Barnhart, Brian A. Ebel
Science and Products
- Science
Calwood Fire "Heil Ranch" Landslide Monitoring Site near Boulder, CO
Wildfire can radically change a mountainous landscape such that even a modest rainstorm is capable of producing deadly and destructive flash flooding and debris flows.Postfire Landslide Monitoring Station: "Chips" (2021 Dixie Fire) near Belden, CA
Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.Postfire Landslide Monitoring Station: "Chambers" (2021 Dixie Fire) near Belden, CA
Wildfire can increase landslide susceptibility in mountainous terrain. The USGS maintains postfire landslide monitoring stations to track hillslope hydrologic conditions in the years following fire.Advancing Post-Fire Debris Flow Hazard Science with a Field Deployable Mapping Tool
Mapping the occurrence of post-fire flooding and debris flow is crucial for 1) integrating observations into models used to define rainfall thresholds for early warning, 2) understanding patterns of inundation, and 3) improving models for predictive hazard assessment. Despite the critical role mapping plays in post-fire hazard assessment and early warning, there has not been a standardized approaHow Often Do Rainstorms Cause Debris Flows in Burned Areas of the Southwestern U.S.?
Debris flows, sometimes referred to as mudslides, mudflows, lahars, or debris avalanches, are common types of fast-moving landslides. They usually start on steep hillsides as a result of shallow landslides, or from runoff and erosion that liquefy and accelerate to speeds in excess of 35 mi/h. The consistency of debris flows ranges from thin, watery to thick, rocky mud that can carry large items...Emergency Assessment of Post-Fire Debris-Flow Hazards
Estimates of the probability and volume of debris flows that may be produced by a storm in a recently burned area, using a model with characteristics related to basin shape, burn severity, soil properties, and rainfall. Wildfire can significantly alter the hydrologic response of a watershed to the extent that even modest rainstorms can produce dangerous flash floods and debris flows. The USGS...2009 Station Fire, Dunsmore Canyon, Glendale, California
In 2009, the Station Fire burned 160,000 acres in the San Gabriel Mountains. Vegetation has started to return, but it can take many years for a basin to fully recover from the effects of fire.Reconstruction of an Avalanche: The West Salt Creek Rock Avalanche
Release Date: MAY 25, 2016 The West Salt Creek Rock Avalanche, Colorado, May 25, 2014Rainfall and Landslides in Southern California
A summary of recent and past landslides and debris flows caused by rainfall in Southern California. - Data
Field-verified inventory of postfire hydrologic response for the 2020 CZU Lightning Complex, River, Camel, and Dolan Fires following a 26-29 January 2021 atmospheric river storm sequence
This data release is a field-verified inventory of postfire hydrologic response for the 2020 CZU (San Mateo–Santa Cruz Unit) Lightning Complex, River Fire, Camel Fire, and Dolan Fire following a 26-29 January 2021 atmospheric river storm sequence. Postfire hydrologic response types include a) no response, b) minor response, and c) major response. A “minor” response was deemed capable of impairingField-verified inventory of postfire debris flows for the 2021 Dixie Fire following a 23-25 October 2021 atmospheric river storm and 12 June 2022 thunderstorm
Summary This data release is a field-verified inventory of postfire debris flows for the 2021 Dixie Fire following a 23-25 October 2021 atmospheric river storm and 12 June 2022 thunderstorm. The “README.txt” file describes the fields for the “Inventory.csv” file. The “Chambers” and “Chips” rain gage data referenced in the inventory are included as: “Chambers-Oct2021-Storm.csv”, “Chambers-Jun2022-SDebris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2019
Chalk Cliffs, located 8 miles southwest of Buena Vista, Colorado, is a natural laboratory for research on runoff-initiated debris flows (Coe et al., 2010). In 2019, there were two monitoring stations operating at Chalk Cliffs. The Upper Station drains an area of 0.06 km2 and was used to monitor flow properties and triggering conditions in the headwaters of the study area. It was equipped with twoDebris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2015
Chalk Cliffs, located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, eDebris-flow and Flood Video Files, Chalk Cliffs, Colorado, USA, 2016
Chalk Cliffs located 8 miles southwest of Buena Vista, Colorado, is one of the most active debris-flow areas in the state (U.S. Geological Survey). Three stations were set up at Chalk Cliffs which are located sequentially along a channel draining the 0.3 km2 study area. These stations are equipped with rain gauges, laser distance meters, and data loggers to record rainfall and stage data (Kean, etData supporting an analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States
This data release supports the analysis of the recurrence interval of post-fire debris-flow generating rainfall in the southwestern United States. We define the recurrence interval of the peak 15-, 30-, and 60-minute rainfall intensities for 316 observations of post-fire debris-flow occurrence in 18 burn areas, 5 U.S. states, and 7 climate types. These data support the analysis described in StaleyDebris-flow monitoring data, Chalk Cliffs, Colorado, USA, 2014
This data release includes 2014 time-series data from three debris-flow monitoring stations at Chalk Cliffs in Chaffee County, Colorado, USA. The data were collected to help identify the triggering conditions, magnitude, and mobility of debris flows at the site. The three stations are located sequentially along a channel draining the 0.3 km^2 study area. The Upper, Middle, and Lower stations haveMonitoring environmental controls on debris-flow sediment supply, Chalk Cliffs, Colorado, 2011 to 2015
This data release includes time-series data of rock temperature, air temperature, wind speed, and humidity at the Chalk Cliffs debris-flow monitoring site in central Colorado (Latitude: 38.73330, Longitude: -106.18704). The data were collected to help identify the environmental controls on rates of rockfall, which is the primary source of debris-flow material at the site. Data were recorded at 1-mPost-wildfire debris-flow monitoring data, Las Lomas, 2016 Fish Fire, Los Angeles County, California, November 2016 to February 2017
This data release includes time-series data from a monitoring site located in a small (0.12 km2) drainage basin in the Las Lomas watershed in Los Angeles County, CA, USA. The site was established after the 2016 Fish Fire and recorded a series debris flows in the first winter after the fire. The station is located along the channel at the outlet of the study area (34 9'18.50"N, 117 56'41.33"W, WGS8Debris-flow inundation and damage data from the 9 January 2018 Montecito Debris-Flow Event
On 9 January 2018, intense rain above Montecito, California triggered a series of debris flows from steep catchments in the Santa Ynez Mountains. These catchments were burned three weeks earlier by the 1140 km2 Thomas Fire. After exiting the mountain front, the debris flows traveled over 3 km down a series of alluvial fans, killing 23 people and damaging over 400 homes. To understand the flow dynaPost-wildfire debris-flow monitoring data, Arroyo Seco, 2009 Station Fire, Los Angeles County, California, November 2009 to March 2010.
This data release includes time-series data from a monitoring site located in a small drainage basin in the Arroyo Seco watershed in Los Angeles County, CA, USA (N3788964 E389956, UTM Zone 11, NAD83). The site was established after the 2009 Station Fire and recorded a series debris flows in the first winter after the fire. The data include three types of time-series: (1) 1-minute time series of raMap and model input and output data covering N 40.0 40.375 and W 105.25 105.625 in the northern Colorado Front Range for analysis of debris flow initiation resulting from the storm of September 9 13, 2013
Rainfall on 913 September 2013 triggered at least 1,138 debris flows in a 3430 km2 area of the Colorado Front Range. Most flows were triggered in response to two intense rainfall periods, one 12.5-hour-long period on 1112 September, and one 8-hour-long period on 12 September. Data in this project pertain to an area bounded by N 40.0 40.375 and W 105.25 105.625 which includes many of the areas wh - Multimedia
- Publications
Filter Total Items: 83
How long do runoff-generated debris-flow hazards persist after wildfire?
Runoff-generated debris flows are a potentially destructive and deadly response to wildfire until sufficient vegetation and soil-hydraulic recovery have reduced susceptibility to the hazard. Elevated debris-flow susceptibility may persist for several years, but the controls on the timespan of the susceptible period are poorly understood. To evaluate the connection between vegetation recovery and dAuthorsAndrew Paul Graber, Matthew A. Thomas, Jason W. KeanToward probabilistic post-fire debris-flow hazard decision support
Post-wildfire debris flows (PFDF) threaten life and property in western North America. They are triggered by short-duration, high-intensity rainfall. Following a wildfire, rainfall thresholds are developed that, if exceeded, indicate high likelihood of a PFDF. Existing weather forecast products allow forecasters to identify favorable atmospheric conditions for rainfall intensities that may exceedAuthorsNina S. Oakley, Tao Liu, Luke McGuire, Matthew Simpson, Benjamin J. Hatchett, Alexander Tardy, Jason W. Kean, Christopher Castellano, Jayme L. Laber, Daniel SteinhoffForecasting the inundation of postfire debris flows
In the semi-arid regions of the western United States, postfire debris flows are typically runoff generated. The U.S. Geological Survey has been studying the mechanisms of postfire debris-flow initiation for multiple decades to generate operational models for forecasting the timing, location, and magnitude of postfire debris flows. Here we discuss challenges and progress for extending operationalAuthorsKatherine R. Barnhart, Ryan P Jones, David L. George, Francis K. Rengers, Jason W. KeanRunout model evaluation based on back-calculation of building damage
We evaluated the ability of three debris-flow runout models (RAMMS, FLO2D and D-Claw) to predict the number of damaged buildings in simulations of the 9 January 2019 Montecito, California, debris-flow event. Observations of building damage after the event were combined with OpenStreetMap building footprints to construct a database of all potentially impacted buildings. At the estimated event volumAuthorsKatherine R. Barnhart, Jason W. KeanPostfire hydrologic response along the central California (USA) coast: Insights for the emergency assessment of postfire debris-flow hazards
The steep, tectonically active terrain along the Central California (USA) coast is well known to produce deadly and destructive debris flows. However, the extent to which fire affects debris-flow susceptibility in this region is an open question. We documented the occurrence of postfire debris floods and flows following the landfall of a storm that delivered intense rainfall across multiple burn aAuthorsMatthew A. Thomas, Jason W. Kean, Scott W. McCoy, Donald N. Lindsay, Jaime Kostelnik, David B. Cavagnaro, Francis K. Rengers, Amy E. East, Jonathan Schwartz, Douglas P. Smith, Brian D. CollinsThe influence of large woody debris on post-wildfire debris flow sediment storage
Debris flows transport large quantities of water and granular material, such as sediment and wood, and this mixture can have devastating impacts on life and infrastructure. The proportion of large woody debris (LWD) incorporated into debris flows can be enhanced in forested areas recently burned by wildfire, because wood recruitment into channels accelerates in burned forests. In this study, we exAuthorsFrancis K. Rengers, Luke A. McGuire, Katherine R. Barnhart, Ann Youberg, Daniel Cadol, Alexander Gorr, Olivia Joan Andrea Khoury Hoch, Rebecca Beers, Jason W. KeanThe rainfall intensity-duration control of debris flows after wildfire
Increased wildfire activity in the western United States has exposed regional gaps in our understanding of postfire debris-flow generation. To address this problem, we characterized flows in an unstudied area to test the rainfall intensity-duration control of the hazard. Our rainfall measurements and field observations from the northern Sierra Nevada (California, USA) show that debris flows resultAuthorsMatthew A. Thomas, Donald N. Lindsay, David B. Cavagnaro, Jason W. Kean, Scott W. McCoy, Andrew Paul GraberSimulating debris flow and levee formation in the 2D shallow flow model D-Claw: Channelized and unconfined flow
Debris flow runout poses a hazard to life and infrastructure. The expansion of human population into mountainous areas and onto alluvial fans increases the need to predict and mitigate debris flow runout hazards. Debris flows on unconfined alluvial fans can exhibit spontaneous self-channelization through levee formation that reduces lateral spreading and extends runout distances compared to unchanAuthorsRyan P. Jones, Francis K. Rengers, Katherine R. Barnhart, David L. George, Dennis M. Staley, Jason W. KeanPostfire debris flow hazards—Tips to keep you safe
Often referred to as “mudflows,” debris flows are a type of landslide made up of a rapidly moving mixture of dirt, rocks, trees, and water (and sometimes ash) that start on a hillside and travel downvalley. They can easily overflow channels and severely damage houses, vehicles, or other structures. Areas burned by wildfires are especially susceptible to these hazards, which can be triggered by stoAuthorsSteven Sobieszczyk, Jason W. KeanMulti-model comparison of computed debris flow runout for the 9 January 2018 Montecito, California post-wildfire event
Hazard assessment for post-wildfire debris flows, which are common in the steep terrain of the western United States, has focused on the susceptibility of upstream basins to generate debris flows. However, reducing public exposure to this hazard also requires an assessment of hazards in downstream areas that might be inundated during debris flow runout. Debris flow runout models are widely availabAuthorsKatherine R. Barnhart, Ryan P. Jones, David L. George, Brian W. McArdell, Francis K. Rengers, Dennis M. Staley, Jason W. KeanMovement of sediment through a burned landscape: Sediment volume observations and model comparisons in the San Gabriel Mountains, California, USA
Post-wildfire changes to hydrologic and geomorphic systems can lead to widespread sediment redistribution. Understanding how sediment moves through a watershed is crucial for assessing hazards, developing debris flow inundation models, engineering sediment retention solutions, and quantifying the role that disturbances play in landscape evolution. In this study, we used terrestrial and airborne liAuthorsFrancis K. Rengers, Luke A. McGuire, Jason W. Kean, Dennis M. Staley, Mariana Dobre, Peter R. Robichaud, Tyson SwetnamPostwildfire soil‐hydraulic recovery and the persistence of debris flow hazards
Deadly and destructive debris flows often follow wildfire, but understanding of changes in the hazard potential with time since fire is poor. We develop a simulation‐based framework to quantify changes in the hydrologic triggering conditions for debris flows as postwildfire infiltration properties evolve through time. Our approach produces time‐varying rainfall intensity‐duration thresholds for ruAuthorsMatthew A. Thomas, Francis K. Rengers, Jason W. Kean, Luke A. McGuire, Dennis M. Staley, Katherine R. Barnhart, Brian A. Ebel - News